IMPORTANCE OF PROPER FLUID LEVEL
It is important that the proper fluid level be maintained at all times because the
transmission fluid cools, lubricates, and transmits hydraulic power. If the fluid
level is too low, the converter and clutches do not receive an adequate supply of
fluid. If fluid level is too high, the fluid can aerate. Aerated fluid can cause the
transmission to shift erratically or overheat.
Emergency Vehicle Series transmissions have an oil level sensor (OLS) that
allows the operator to obtain an indication of fluid level from the shift selector.
However, no oil level sensor diagnostics take place unless the OLS is
“autodetected” by Allison 4
th
Generation Controls or WTEC III Controls.
Frequently check for the presence of oil level diagnostics if the transmission is
known to contain an OLS. If an OLS is not detected during a fixed number of
engine starts, the WTEC III or Allison 4
th
Generation Controls system concludes
that no OLS is present. If an OLS is known to be present, but has not been
detected, then troubleshooting of the OLS circuit is required. After the OLS circuit
is repaired, reset “autodetect” or manually select the OLS function using Allison
DOC™ For PC–Service Tool. For detailed troubleshooting procedures refer to the
Troubleshooting Manual. Refer to the SERVICE LITERATURE section for
specific publication numbers.
NOTE: To correctly check the transmission fluid level using the
dipstick, the transmission fluid must be at operating temperature.
The oil level sensor method of checking the fluid level compensates for
transmission fluid temperature between 60°C–104°C (140°F–220°F).
Any temperature below 60°C (140°F) or above 104°C (220°F) will
result in an Invalid for Display condition.
FLUID LEVEL CHECK USING PUSHBUTTON OR LEVER
SHIFT SELECTOR
The transmission must be equipped with the oil level sensor to be able to read
fluid level information.
NOTE: WTEC III Controls pushbutton and lever selectors display fluid
level diagnostic information one character at a time. Allison 4
th
Generation Controls pushbutton and lever selectors display fluid level
diagnostic information two characters at a time.
1. Park the vehicle on a level surface, shift to N (Neutral), and apply the
parking brake.
50
To Next Page
Loading...
Need help?
General
